How to get a vector position in a string and store it as integers?

Question

There's plenty of these questions on SO, but I'm finding none specific to this case by extracting a vector coordinates to integer values.

I'm parsing the current string:

"AT (1,1) ADDROOM RM0001"

I need to get the numbers between (#,#) and store them as integers.

One solution I tried was get the index of the first '('. Read in the string until a comma is met, and then read again until the last ')' is met. Another solution I tried was find the ',' and get the string prior and after it before meeting a parenthesis.

I keep feeling this is error-prone though. I feel there's an easier way to do this if reading from the string. I was researching on Regex.

Answer 1

This is the regex you need:

\((-?\d+)\s*,\s*(-?\d+)\)

You can use it like this:

var match = Regex.Match("some string (1234, -5678)", @"\((-?\d+)\s*,\s*(-?\d+)\)")
var x = match.Groups[1].Value;
var y = match.Groups[2].Value;

x and y will be the two components of the vector.

Explanation:

• \( open parenthesis
• (-?\d+) first capturing group that captures the first component of the vector. The - is optional (so both positive and negative integers are matched) followed by 1 or more digits (\d). This same thing appears again later in the regex to capture the second component
• \s* this allows any number of whitespace between the numbers and the comma
• \) close parenthesis

For a lower level explanation, go to https://regex101.com/r/PnwBJS/1 and look at the "explanation" section.